1. FIELD OF THE INVENTION
This invention relates to a sliding surface working method using wire-explosion spray coating, and particularly to a sliding surface working method using wire-explosion spray coating, according to which cylinders for use in internal combustion engines having good wear resistance, peel resistance and seizure resistance characteristics and uniform quality can be inexpensively mass-produced without coproduction of an effluent which causes environmental contamination.
2. DESCRIPTION OF THE PRIOR ART
Heretofore, cast iron cylinders or aluminium cylinders having a cast iron liner have been utilized as cylinders for use in internal combustion engines. However, in the modern high performance and high power engine, the conventional cylinder has become insufficient because of its poor cooling characteristics, and this has become a large problem in the production of engine. Recently, in order to overcome this problem, chromium plated aluminium cylinders having the inner sliding surface plated with chromium are being adopted for some applications. However, production of such cylinders relies on a plating process which produces a waste liquor effluent and thus entails a possibility of causing environmental pollution. Further, such a process requires an installation of large scale and the time required for pretreatment, processing and after-treatment is very long. Accordingly, the number of man-hours required per unit is large and the manufacturing cost is correspondingly high.
On the other hand, there have been proposed many kinds of methods for providing metal coating on the inner sliding surface of an aluminium base cylinder by flame-spray coating and the like. In these methods, it has also been known to pre-form a molybdenum bonding layer on the base material by flame-spraying to increase the degree of bonding between the base material and the coating layer.
In the conventional flame-spray coating, however, it has been difficult to inexpensively massproduce cylinders having flame-sprayed coating layer of high density and high smoothness.